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			313 lines
		
	
	
	
		
			8.5 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			313 lines
		
	
	
	
		
			8.5 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
/*
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    This file is part of TON Blockchain Library.
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    TON Blockchain Library is free software: you can redistribute it and/or modify
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    it under the terms of the GNU Lesser General Public License as published by
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    the Free Software Foundation, either version 2 of the License, or
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    (at your option) any later version.
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    TON Blockchain Library is distributed in the hope that it will be useful,
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    but WITHOUT ANY WARRANTY; without even the implied warranty of
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    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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    GNU Lesser General Public License for more details.
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    You should have received a copy of the GNU Lesser General Public License
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    along with TON Blockchain Library.  If not, see <http://www.gnu.org/licenses/>.
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    Copyright 2017-2020 Telegram Systems LLP
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*/
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#include "td/utils/base64.h"
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#include "td/utils/common.h"
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#include "td/utils/Slice.h"
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#include "td/utils/Status.h"
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#include <algorithm>
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#include <iterator>
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namespace td {
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template <bool is_url>
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static const char *get_characters() {
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  return is_url ? "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_"
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                : "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
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}
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template <bool is_url>
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static const unsigned char *get_character_table() {
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  static unsigned char char_to_value[256];
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  static bool is_inited = [] {
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    auto characters = get_characters<is_url>();
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    std::fill(std::begin(char_to_value), std::end(char_to_value), static_cast<unsigned char>(64));
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    for (unsigned char i = 0; i < 64; i++) {
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      char_to_value[static_cast<size_t>(characters[i])] = i;
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    }
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    return true;
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  }();
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  CHECK(is_inited);
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  return char_to_value;
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}
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template <bool is_url>
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string base64_encode_impl(Slice input) {
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  auto characters = get_characters<is_url>();
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  string base64;
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  base64.reserve((input.size() + 2) / 3 * 4);
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  for (size_t i = 0; i < input.size();) {
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    size_t left = min(input.size() - i, static_cast<size_t>(3));
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    int c = input.ubegin()[i++] << 16;
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    base64 += characters[c >> 18];
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    if (left != 1) {
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      c |= input.ubegin()[i++] << 8;
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    }
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    base64 += characters[(c >> 12) & 63];
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    if (left == 3) {
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      c |= input.ubegin()[i++];
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    }
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    if (left != 1) {
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      base64 += characters[(c >> 6) & 63];
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    } else if (!is_url) {
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      base64 += '=';
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    }
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    if (left == 3) {
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      base64 += characters[c & 63];
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    } else if (!is_url) {
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      base64 += '=';
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    }
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  }
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  return base64;
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}
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string base64_encode(Slice input) {
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  return base64_encode_impl<false>(input);
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}
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string base64url_encode(Slice input) {
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  return base64_encode_impl<true>(input);
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}
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template <bool is_url>
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Result<Slice> base64_drop_padding(Slice base64) {
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  size_t padding_length = 0;
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  while (!base64.empty() && base64.back() == '=') {
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    base64.remove_suffix(1);
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    padding_length++;
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  }
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  if (padding_length >= 3) {
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    return Status::Error("Wrong string padding");
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  }
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  if ((!is_url || padding_length > 0) && ((base64.size() + padding_length) & 3) != 0) {
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    return Status::Error("Wrong padding length");
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  }
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  if (is_url && (base64.size() & 3) == 1) {
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    return Status::Error("Wrong string length");
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  }
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  return base64;
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}
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static Status do_base64_decode_impl(Slice base64, const unsigned char *table, char *ptr) {
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  for (size_t i = 0; i < base64.size();) {
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    size_t left = min(base64.size() - i, static_cast<size_t>(4));
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    int c = 0;
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    for (size_t t = 0; t < left; t++) {
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      auto value = table[base64.ubegin()[i++]];
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      if (value == 64) {
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        return Status::Error("Wrong character in the string");
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      }
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      c |= value << ((3 - t) * 6);
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    }
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    *ptr++ = static_cast<char>(static_cast<unsigned char>(c >> 16));  // implementation-defined
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    if (left == 2) {
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      if ((c & ((1 << 16) - 1)) != 0) {
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        return Status::Error("Wrong padding in the string");
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      }
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    } else {
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      *ptr++ = static_cast<char>(static_cast<unsigned char>(c >> 8));  // implementation-defined
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      if (left == 3) {
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        if ((c & ((1 << 8) - 1)) != 0) {
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          return Status::Error("Wrong padding in the string");
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        }
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      } else {
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        *ptr++ = static_cast<char>(static_cast<unsigned char>(c));  // implementation-defined
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      }
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    }
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  }
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  return Status::OK();
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}
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template <class T>
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static T create_empty(size_t size);
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template <>
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string create_empty<string>(size_t size) {
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  return string(size, '\0');
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}
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template <>
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SecureString create_empty<SecureString>(size_t size) {
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  return SecureString{size};
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}
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template <bool is_url, class T>
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static Result<T> base64_decode_impl(Slice base64) {
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  TRY_RESULT_ASSIGN(base64, base64_drop_padding<is_url>(base64));
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  T result = create_empty<T>(base64.size() / 4 * 3 + ((base64.size() & 3) + 1) / 2);
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  TRY_STATUS(do_base64_decode_impl(base64, get_character_table<is_url>(), as_mutable_slice(result).begin()));
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  return std::move(result);
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}
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Result<string> base64_decode(Slice base64) {
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  return base64_decode_impl<false, string>(base64);
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}
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Result<SecureString> base64_decode_secure(Slice base64) {
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  return base64_decode_impl<false, SecureString>(base64);
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}
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Result<string> base64url_decode(Slice base64) {
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  return base64_decode_impl<true, string>(base64);
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}
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template <bool is_url>
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static bool is_base64_impl(Slice input) {
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  size_t padding_length = 0;
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  while (!input.empty() && input.back() == '=') {
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    input.remove_suffix(1);
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    padding_length++;
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  }
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  if (padding_length >= 3) {
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    return false;
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  }
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  if ((!is_url || padding_length > 0) && ((input.size() + padding_length) & 3) != 0) {
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    return false;
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  }
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  if (is_url && (input.size() & 3) == 1) {
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    return false;
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  }
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  auto table = get_character_table<is_url>();
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  for (auto c : input) {
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    if (table[static_cast<unsigned char>(c)] == 64) {
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      return false;
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    }
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  }
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  if ((input.size() & 3) == 2) {
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    auto value = table[static_cast<int>(input.back())];
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    if ((value & 15) != 0) {
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      return false;
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    }
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  }
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  if ((input.size() & 3) == 3) {
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    auto value = table[static_cast<int>(input.back())];
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    if ((value & 3) != 0) {
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      return false;
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    }
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  }
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  return true;
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}
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bool is_base64(Slice input) {
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  return is_base64_impl<false>(input);
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}
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bool is_base64url(Slice input) {
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  return is_base64_impl<true>(input);
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}
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template <bool is_url>
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static bool is_base64_characters_impl(Slice input) {
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  auto table = get_character_table<is_url>();
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  for (auto c : input) {
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    if (table[static_cast<unsigned char>(c)] == 64) {
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      return false;
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    }
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  }
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  return true;
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}
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bool is_base64_characters(Slice input) {
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  return is_base64_characters_impl<false>(input);
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}
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bool is_base64url_characters(Slice input) {
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  return is_base64_characters_impl<true>(input);
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}
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string base64_filter(Slice input) {
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  auto table = get_character_table<false>();
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  string res;
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  res.reserve(input.size());
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  for (auto c : input) {
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    if (table[static_cast<unsigned char>(c)] != 64 || c == '=') {
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      res += c;
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    }
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  }
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  return res;
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}
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static const char *const symbols32_lc = "abcdefghijklmnopqrstuvwxyz234567";
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static const char *const symbols32_uc = "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567";
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string base32_encode(Slice input, bool upper_case) {
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  auto *symbols32 = (upper_case ? symbols32_uc : symbols32_lc);
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  string base32;
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  base32.reserve((input.size() * 8 + 4) / 5);
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  uint32 c = 0;
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  uint32 length = 0;
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  for (size_t i = 0; i < input.size(); i++) {
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    c = (c << 8) | input.ubegin()[i];
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    length += 8;
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    while (length >= 5) {
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      length -= 5;
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      base32.push_back(symbols32[(c >> length) & 31]);
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    }
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  }
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  if (length != 0) {
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    base32.push_back(symbols32[(c << (5 - length)) & 31]);
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  }
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  //TODO: optional padding
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  return base32;
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}
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static unsigned char b32_char_to_value[256];
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static void init_base32_table() {
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  static bool is_inited = [] {
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    std::fill(std::begin(b32_char_to_value), std::end(b32_char_to_value), static_cast<unsigned char>(32));
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    for (unsigned char i = 0; i < 32; i++) {
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      b32_char_to_value[static_cast<size_t>(symbols32_lc[i])] = i;
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      b32_char_to_value[static_cast<size_t>(symbols32_uc[i])] = i;
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    }
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    return true;
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  }();
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  CHECK(is_inited);
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}
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Result<string> base32_decode(Slice base32) {
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  init_base32_table();
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  string res;
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  res.reserve(base32.size() * 5 / 8);
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  uint32 c = 0;
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  uint32 length = 0;
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  for (size_t i = 0; i < base32.size(); i++) {
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    auto value = b32_char_to_value[base32.ubegin()[i]];
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    if (value == 32) {
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      return Status::Error("Wrong character in the string");
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    }
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    c = (c << 5) | value;
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    length += 5;
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    while (length >= 8) {
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      length -= 8;
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      res.push_back(td::uint8((c >> length) & 255));
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    }
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  }
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  if ((c & ((1 << length) - 1)) != 0) {
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    return Status::Error("Nonzero padding");
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  }
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  //TODO: check padding
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  return res;
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}
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}  // namespace td
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